Development of a multigrid finite difference solver for benchmark permeability analysis

A finite difference solver, dedicated to flow around fibre architectures is currently being developed. The complexity of the internal geometry of textile reinforcements results in extreme computation times, or inaccurate solutions. A compromise between the two is found by implementing a multigrid algorithm and analytical solutions at the coarsest level of discretisation. Hence, the computational load of the solver is drastically reduced.\ud This paper discusses the main features of the 3D multigrid algorithm implemented as well as the implementation of the analytical solution in the finite difference scheme. The first tests of the solver on the permeability benchmark lithographic reference geometry are discussed.\ud Several tests were performed to assess the accuracy and the reduction in calculation time. The methods prove to be both accurate and efficient. However, the code is developed in Matlab© and hence is relatively slow. A C++ code is currently under development to achieve acceptable calculation times

Persuasive Ways to Change Entrance Use of Buildings

People tend to use the same door every time they enter and exit a building. When certain entrances are widely preferred over others, congestion can occur. This paper describes two interventions to persuade visitors to use another entrance. The first intervention used sensory deprivation (darkness), and the second used guidance paths. The first intervention on sensory deprivation had the expected outcome. This intervention resulted in an avoidance of the darkened door. The second intervention had a result contrary to the expectations; it resulted in an increased preference for the door without guidance paths

Passive Observations of a Large DNS Service:2.5 Years in the Life of Google

In 2009 Google launched its Public DNS service, with its characteristic IP address 8.8.8.8. Since then, this service has grown to be the largest and most well-known DNS service in existence. The popularity of public DNS services has been disruptive for Content Delivery Networks (CDNs). CDNs rely on IP information to geo-Iocate clients. This no longer works in the presence of public resolvers, which led to the introduction of the EDNSO Client Subnet extension. ECS allows resolvers to reveal part of a client's IP address to authoritative name servers and helps CDNs pinpoint client origin. A useful side effect of ECS is that it can be used to study the workings of public DNS resolvers. In this paper, we leverage this side effect of ECS to study Google Public DNS. From a dataset of 3.7 billion DNS queries spanning 2.5 years, we extract ECS information and perform a longitudinal analysis of which clients are served from which Point-of-Presence. Our study focuses on two aspects of GPDNS. First, we show that while GPDNS has PoPs in many countries, traffic is frequently routed out of country, even if that was not necessary. Often this reduces performance, and perhaps more importantly, exposes DNS requests to state-level surveillance. Second, we study how GPDNS is used by clients. We show that end-users switch to GPDNS en masse when their ISP's DNS service is unresponsive, and do not switch back. We also find that many e-mail providers configure GPDNS as the resolver for their servers. This raises serious privacy concerns, as DNS queries from mail servers reveal information about hosts they exchange mail with. Because of GPDNS's use of ECS, this sensitive information is not only revealed to Google, but also to any operator of an authoritative name server that receives ECS-enabled queries from GPDNS during the lookup process

OCP acquires FTTH player

PURPOSE OF REVIEW: In this review, we highlight the most important cellular and molecular mechanisms that contribute to cardiac inflammation and fibrosis. We also discuss the interplay between inflammation and fibrosis in various precursors of heart failure (HF) and how such mechanisms can contribute to myocardial tissue remodelling and development of HF. RECENT FINDINGS: Recently, many research articles attempt to elucidate different aspects of the interplay between inflammation and fibrosis. Cardiac inflammation and fibrosis are major pathophysiological mechanisms operating in the failing heart, regardless of HF aetiology. Currently, novel therapeutic options are available or are being developed to treat HF and these are discussed in this review. A progressive disease needs an aggressive management; however, existing therapies against HF are insufficient. There is a dynamic interplay between inflammation and fibrosis in various precursors of HF such as myocardial infarction (MI), myocarditis and hypertension, and also in HF itself. There is an urgent need to identify novel therapeutic targets and develop advanced therapeutic strategies to combat the syndrome of HF. Understanding and describing the elements of the inflammatory and fibrotic pathways are essential, and specific drugs that target these pathways need to be evaluated

Quantification of the influence of external vibrations on the measurement error of a coriolis mass-flow meter

In this paper the influence of external vibrations on the measurement value of a Coriolis mass-flow meter (CMFM) for low flows is investigated and quantified. Model results are compared with experimental results to improve the knowledge on how external vibrations affect the mass-flow measurement value. A flexible multi-body model is built and the working principle of a CMFM is explained. Some special properties of the model are evaluated to get insight into the dynamic behaviour of the CMFM. Using the model, the transfer functions between external vibrations (e.g. floor vibrations) and the flow error are derived. The external vibrations are characterised with a PSD. Integrating the squared transfer function times the PSD over the whole frequency range results in an RMS flow error estimate. In an experiment predefined vibrations are applied on the casing of the CMFM and the error is determined. The experimental results show that the transfer functions and the estimated measurement error correspond with the model results. The agreement between model and measurements implies that the influence of external vibrations on the measurement is fully understood. This result can be applied in two ways; firstly that the influence of any external vibration spectrum on the flow error can be estimated and secondly that the performance of different CMFM designs can be compared and optimised by shaping their respective transfer function